#define _CRT_SECURE_NO_WARNINGS 1

#include <stdio.h>


int main() {
    int n = 0;
    int time = 0;
    int m, l;
    scanf("%d", &n);
    if (n <= 11)
    {
        time = 2;
    }
    else
    {
        m = n / 12;
        time = m * 4;
        time += 2;
    }
    printf("%d\n", time);
    return 0;
}
